Diamond drill bit for rotary well drilling



J. A. ZUBLIN DIAMOND DRILL BIT FOR ROTARY WELL DRILLING Filed July 26, 1951 Oct.

2 SHEETSSHEET l ATTORNEYS my A Oct. 21, 1952 J. A. ZUBLIN DIAMOND DRILL BIT FOR ROTARY WELL DRILLING Filed July 26, 1951 2 -SHEETS SHEET 2 JbfilaA. 111.5%

flan/ML? ATTORNEYS ac 000K OM MO 0 00000 W can coooaoao O 0 I5 J 0%.00 H oowwvo 1; W L w 00 0 0 00 Patented Oct. 21, 1952 DIAMOND DRILL BIT FORROTARY WELL DRILLING John A. Zublin, Los Angeles, Calif. Application July 26, 1951, Serial-No. 238,637

1 This inventionrelates to a novel diamond drill bit more particularly adapted for drilling in extremelyhard formations. The bit is especially applicableto the drilling of relatively small diameter bores deviating from existing well bores.

9 Diamond rotary core bits have been in use for a number of years which. are effective to cut a core having a diameter equal to the interior diameter of a hollow core bit. Commercially, diamond drill bits have been largely limited to core drilling because the diamond cutting elements do not have great resistance to shock or impact loads. The drilling of open well bores with diamond drill bits, that is, bits studded with diamond cutting elements, has presented problem which have not, to applicants knowledge, been heretofore satisfactorily solved. The cutting of a clean bore,ofcourse, necessitates removal of the formation at the exact center of the well bore as well as at the periphery thereof. A diamond cutting element positioned at the center of the well bore, of course, merely rotates about its own 6 Claims. (01. 255-6l) bit.

axisand will not long effectively perform any satisfactory cutting operation and, furthermore, will-soonshatter because of its inability to stand the strain.

It is among thepurposes and objects of the present invention to provide a diamond drill bit which is effective in drilling an open bore and which will have long life in operation. in the drilling of hard formations.

More specifically, it is an object of the invention to provide a diamond drill bit effective to remove the outer portion, 1. e., peripheral portion, of the formation of the bottom of the bore being drilled while the inner or central portion is allowed to protrude into the bit in the form of a cone, the apex of which coincides with the axis of rotationof the bit.

, Through the provision of a diamond bit having a conical recess the exposed wall of which is studded with diamonds, the cone of the formation which extends into the conical recess of the bit is continuously cut away as the drilling proceeds and the diamond cutting elements near the apex of the conical recess of the bit are subjected to relatively little strain since, at that point, the formation being cut is of exceedingly small diameter and easily sheared or broken off.

It is a further and more specific object of the invention to provide the conically recessed diamond studded bit with channels for the circulating fluid which will be effective to free the cutting face of the bit from unwanted detritus.

It is afurther and more specific object of the inventiontoprovide a diamond cutting bit having a central conical recess which communicates with a channel for receiving cut-away: portions of the formation.

It is a further and more specific object'of the invention to provide a diamond drill bit having a conical recess in the cutting face thereof which Will be effective under the drilling weight applied to the bit to shear. and break off the central portion of the formation being .removed' by th Further and more specific objects of the in-- vention will become apparentas the description proceeds, which will be given by reference to the accompanying drawings, wherein Figure l is a side elevational View of the diamond drill bit conforming to the present invention. v

Figure 21s a bottom plan view of the bit shown inFigure l.

Figure 3 is a cross-sectional viewalong the line 3-3 of Figure 2.

Figure 4 is a fragmentary view similar to Figure 3 but disclosing the bit as itappears in action in the drilling of a well bore.

Figure 5 is a cross-sectional View of a modified form of the invention.

Figure 6 is. a cross-sectional view through the complete bit of the modification shown in Figure 5 taken in thedirection of the arrows on the plane of the line 6-6 of Figure 5, and

Figure 7 is a detailed view of the removable element of a modification of Figure 5.

Referring to Figure 1, the bit body it has a threaded shank H by which it is adapted to be secured to the lower end of a suitable drill string section for rotationtherewitha The bit body lil andshank II have an open channel 12 extending therethrough. The channel 12 is circular .atits upper portion but is offset as indicated at l3 and takes the form of a flared semicircular chamber I 4 which it will be observed is disposed entirely to one side of a plane perpendicular to'Figure 3 extending through the axis AA of the bit. The

' bit body I 0 has a conical recess defined by the wall I5 to which wall a diamond cutting element carrying matrix It is suitably adhered so that, in efcry of the bit and are out where they communicate with vertical channels 2|, 22 and 23 respectively. The grooves l82ll and channels 2 l23 provide free flow passageways for the circulating fluid employed in the drilling operation which is forced downwardly through the channel H2 in shank II thence through the offset portion l3 of the channel into the semicircular chamber 14 thence through the respective grooves l8'2il and then upwardly through the channels 2 l23. The lands or spaces between the grooves l8, I9 and 26 and their channel extensions 25, 22 and 23, which lands are designated 24, 25 and 26, carry heterogeneously mounted throughout their exposed areas diamond cutting elements 27.

In operation the entire bit is, of course, rotated by the rotary drill string which extends to the surface of the well. By reference to Figure 4 it will be observed that the matrix 16 embracing its annular upturned portion l'i provides an annular formation cutting face 28 which acts to cut a groove in the formation extending around the circumference of the bore. annular cutting face 28 penetrates the formation the upwardly extending lands 2 B, 25 and 25 carrying the diamond cutting elements 2'! cut away what would otherwise be a circular core until it takes the form of a cone designated 28 having the apex D in the axis of rotation A-A of the bit. The bit is,'of course, impelled downwardly by the pressure P through imposition of weight on bit at the surface of the well. The semicircular opening Iii terminates along the line F-F.

It will thus be apparent that that portion of the cone 29 which lies above the plane of the line F-F and to the left of a plane perpendicular to 'Figure 4 passing through the axis AA of the bit will be fully exposed in the semicircular opening M. face of the bit above the plane of the line FF' is therefore available to carry diamond cutting elements 2i. Under the pressure P representing the weight on bit the cone 29 gradually moves up into the conical recess of the bit, the lower part being cut away at the cutting face 28 and by the diamond cutting elements mounted in the lands a l, 25 and 26. The upper part of the cone 29, of course, has materially less surface and there are materially less diamond cutting elements acting on it. Thus, at the apex D of the cone 29 and for a distance somewhat therebelow, the cone will not be cut away as rapidly as it is at lower portions of its conical surface and there will be a tendency for the cone to bulge out slightly as it approaches the apex D which gives riseto a pressure component indicated Pl in Figure l. The greater the tendency of the cone to bulge out near the apex, the greater will be the pressure P! and this pressure is, of course, always directly opposite the semicircular opening Hi and is available to shear and break off the point of the cone above the plane passing through line F--F'. The harder the formation, the nearer the apex D the cone will be sheared or broken away. In softer formations it may well break away near the line FF. The chamber E4 is of sufiicient size to hold a considerable volume of pieces of formation broken away and sheared away from the cone. These are carried down through the grooves l8, l9 and 2e, are further reduced in size and ultimately carried by the circulating fluid upwardly through the channels 2!, 22 and 23 and removed from the bottom of th well bore.

As the Only one half of the conical sur-' If the action of the bit slows down, indicating the chamber I l may have become filled with broken cone pieces, the pump pressure on the circulating fluid will rise, indicating to the driller at the surface of the well the circumstance that the chamber M has become filled or clogged. The driller can then raise the bit for a foot or so from the bottom of the well and the circulating fluid will free the channel [2 and chamber i l of all the pieces which have collected therein. These will fall into the annular circular groove around the cone and when the bit is again lowered they will be pulverized and removed.

From the foregoing it will be appreciated that the diamond drill bit of the present invention is not dependent to any great extent upon effec tlve cuttin of the diamond cutting elements at the point of dead center of the bit. Indeed, the bit will be effective after the diamond cutting elements near the apex D and conical recess of the bit are substantially worn out.

In Figures 5, 6 and 7 there is shown a modified form of the invention in which the bit body 36 is recessed at El to receive a specially formed plug 32 more particularly shown in Figure 7. The plug 32 seats against the annular shoulder 3'3 in the recess 3! at its upper end and is held in position in the bit body 30 by the screws 34 and 355. The plug 32 has a semicircular cut-out portion 36 to provide a semicircular chamber quite comparable to chamber [4 of the modification of Figures 1-4. The semicircular chamber 33 communicates with the channel 3! in the shank 38. The diamond cutting element supporting matrix 39 is provided with a series of cut-out grooves it and vertical extending channels M. The plug 32 is so positioned in the recess 23! that three of the grooves 40 open into the semicircular chamber 36 since three of these grooves are positioned to one side of the vertical plane passing through the axis of rotation of the bit (see Figure 6). The lands between the grooves ill carry heterogeneously mounted diamond cutting elements comparable to the diamend cutting elements 27 in the modification of Figures 1 to 4, and that portion of the plug 32 below the point 42 has a frusta-conical surface which provides an extension of the conical cutting face directly opposed to the semicircular chamber 36. The operation of the modified form of invention as disclosed in Figures 5-7 is the same as the preferred embodiment illustrated in Figures 1-4 and may be resorted to to facilitate ease of manufacture. In all forms of the invention the action of the bit results in the production of a cone or formation extending into the conical recess of the bit, the apex of which is sheared and broken away by the action of a component of pressure applied to the bit in the rotary drilling operation.

Having thus described my invention, what I claim is:

1. A diamond drill bit for drilling in hard formations, comprising a bit body, a channel extending downwardly through said bit body, a conically shaped recess in the bottom of said bit body, the apex of said conical recess lying substantially in the axis of rotation of said bit, a portion of said conical surface less than its circumference being cut away near the apex thereof to provide an open communication from said channel into said conically shaped recess, the uncut-away portion of said conical surface being effective under the weight on the bit to continually break away the apex of the conical forma- 5 tion produced by said bit during progressive drilling thereby, a plurality of grooves cut in and extending from said open communication to the periphery of said bit, the sections of said conical surface intermediate said grooves carrying het erogeneously mounted diamond cutting elements at least one of said sections of said conical surface terminating substantially at the center of rotation of said bit, and at least one of said sections terminating short of the center of rotation of said bit.

2. A diamond drill bit for drilling in hard forr mations comprising a bit body, a generally conically shaped recess in the bottom of said bit body, a channel extending downwardly through said bit body and opening into said conical recess well above the base of said bit, a plurality of grooves cut in the conical surface of said conical recess extending from said channel to the periphery of said bit, the segmental sections intermediate said grooves carrying heterogeneously mounted diamond cutting elements, at least one of said segmental sections of said conical surface terminating substantially at the center of rotation of said bit, and at least one of said sections terminating short of the center of rotation of said bit.

3. A diamond drill bit for drilling in hard formations comprising a bit body, a generally conically shaped recess in the bottom of said bit body, a channel extending downwardly through said bit body and opening into said conical recess well above the base of said bit, a plurality of grooves cut in the conical surface of said conical recess extending from said channel to the periphery of said bit and extending upwardly from the base of the said bit a substantial distance on the outer wall of the bit body, the segmental sections intermediate said grooves carrying heterogeneously mounted diamond cutting elements, at least one of said segmental sections of said conical surface terminating substantially at the center of rota- ,tion of said bit, and at least one of said sections terminating short of the center of rotation of said bit.

4. A diamond drill bit for drilling in hard formations comprising a bit body, a generally conically shaped recess in the bottom of said bit body, a channel extending downwardly through said bit body and opening into said conical recess well above the base of said bit, a plurality of grooves cut in the conical surface of said conical recess extending from said channel to the periphery of said bit, the cross sectional area of said channel being greater than the total cross sectional area of said grooves, the segmental sections intermediate said grooves carrying heterogeneously mounted diamond cutting elements, at least one of said segmental sections of said conical surface terminating substantially at the center of rotation of said bit, and at least one of said sections terminating short of the center of rotation of said bit.

5. A diamond drill bit for drilling in hard forgeneously mounted diamond cutting elements, at least one of said segmental sections of said conical surface terminating substantially at the center of rotation of said bit, and at least one of said sections terminating short of the center of rotation of said bit.

6. A diamond drill bit for drilling in hard. formations comprising a bit body, a fluid conducting passageway extending downwardly through said bit body, a substantially conically shaped recess in the bottom of said bit body, the center of said conical recess lying substantially in the axis of rotation of said bit body, said fluid conducting passageway opening into said conical recess, a plurality of grooves cut in the wall of said conical recess and extending from said passageway to the periphery of said bit dividing the surface of said conical recess into a plurality of sections each of which carries heterogeneously mounted diamond cutting elements, at least one of said sections extending substantially to the axis of rotation of said bit body, said bit body embracing a removable and replaceable element, a portion of which is adapted to form a part of said section extending substantially to the axis of rotation of said bitbody, and at least one of said sections terminating short of the center of rotation of said bit.

JOHN A. ZUBLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

